Recently, various types of information recording mediums are used to record digital data. For example, a rewritable optical disc or a write-once optical disc is used. In the rewritable optical disc, data can be rewritten repeatedly at the same location. In the write-once optical disc, data can be written only once at the same location, while it is inexpensive.
As an example of rewritable optical discs, there are DVD-RAM discs and BD-RE (Blu-ray Disc Rewritable) discs and the like.
As an example of write-once optical discs, there are DVD-R discs and BD-R (Blu-ray Disc Recordable) discs and the like.
In the rewritable optical disc, a defective management mechanism is introduced to improve the reliability of data recorded on the disc.
The defective management mechanism includes a slipping replacement algorithm and a linear replacement algorithm.
The slipping replacement algorithm is mainly performed when the disc is formatted. In the slipping replacement algorithm, all of the ECC clusters in the user data area are checked for detecting a defective cluster. When the defective cluster is found, the location of the defective cluster is registered to a primary defect list (hereinafter, “PDL”). The logical cluster corresponding to the defective cluster is shifted such that the logical cluster corresponds to a physical cluster which is next to the physical cluster corresponding to the defective cluster.
Thus, when the user data is recorded, it is possible to avoid recording the user data in the defective cluster registered in the PDL. As a result, it is possible to improve the reliability of the data recording.
The linear replacement algorithm is performed when a user data is recorded.
After the user data is recorded, a verify process is performed. In the verify process, the recording result is verified. If the data recording has failed, the ECC cluster including the recording location is determined as a defective cluster. Then, the location of the defective cluster is managed by a secondary defect list (hereinafter, “SDL”).
The user data is recorded in the spare area which is located at the inner-most periphery or the outer-most periphery on the disc, instead of the defective cluster in the user data area.
The verify process described above is performed during the replacement recording. If the data recording has succeeded, the location at which the user data is recorded is determined. An SDL entry which correlates the location of the defective cluster with an ECC cluster for replacement is generated. Then, the SDL entry is registered to the SDL.
The SDL entry is provided for each of the all ECC clusters included in the spare area. It is possible to manage whether or not each ECC cluster in the spare area is available as a replacement cluster. If the ECC cluster is an unrecorded area in the spare area, then the ECC cluster is available as a replacement cluster. If the ECC cluster is a recorded area in the spare area, then the ECC cluster is not available as a replacement cluster. The unrecorded area in the spare area is also called a spare cluster.
In the reproduction process, by referring to the PDL and the SDL, if necessary, the data is reproduced from the replacement cluster.
The PDL and the SDL are recorded in a defect management area (hereinafter, “DMA”) provided in the lead-in area on the disc. In the DMA, information indicating the size of the spare area and the like is further recorded.
In the rewritable optical disc, the information on the defective management is updated by rewriting the DMA.
In the write-once optical disc, it is possible to introduce a defective management mechanism, for example, as described in the specification of U.S. laid-open patent publication No. 2004/0076096 (hereinafter, “reference 1”).
FIG. 3 of the reference 1 shows a data structure of the disc. In the disc of the reference 1, the DMA is provided in the lead-in area and the lead-out area.
Further, a temporary defect management area (hereinafter, “TDMA”) is provided in the lead-in area and the lead-out area.
In the write-once optical disc, the information on the defective management is updated by additionally recording defective information in the TDMA each time the defective information is updated.
When the disc is closed or finalized, the data in the latest TDMA is recorded in the DMA.
In the TDMA, temporary defect management information (hereinafter, “TDDS”) and temporary defect information (hereinafter, “TDFL”) are recorded.
FIG. 5B of the reference 1 shows a data structure of the TDDS. The TDDS includes pointer information to the TDFL. The TDFL can be recorded in the TDMA a plurality of times. The pointer information is recorded for the respective TDFLs.
In the TDDS, a last recorded address on the write-once optical disc is recorded. As shown in FIG. 5B of the reference 1, a single write-once optical disc can have a plurality of last recorded addresses.
In the TDDS, a last recorded replacement address on the write-once optical disc is recorded. As shown in FIG. 5B of the reference 1, a single write-once optical disc can have a plurality of last recorded replacement addresses.
FIG. 6 of the reference 1 shows a data structure of the TDFL.
The TDFL includes information regarding defect #1, #2, . . . and the like.
The information regarding defect includes status information, a pointer to the defective cluster and a pointer to the replacement cluster.
The information regarding defect has a data structure similar to the SDL entry included in the SDL. The information regarding defect performs a function similar to the SDL entry.
FIGS. 33A and 33B show a method for updating the TDFL disclosed in FIG. 9A and FIG. 9B of the reference 1.
FIG. 33A shows a data structure of the TDFL #0. The TDFL #0 includes the information regarding defect #1, #2 and #3 corresponding to the defects #1, #2 and #3.
After the TDFL #0 is recorded, it is assumed that the defects #4 and #5 are detected as a result of performing a new data recording. In this case, the TDFL #1 shown in FIG. 33B is recorded on the write-once optical disc.
The TDFL #1 is generated by maintaining the information regarding defect #1, #2 and #3 included in the TDFL #0 and adding the information regarding defect #4 and #5 corresponding to the defects #4 and #5.
FIG. 10 of the reference 1 shows a data structure of the information regarding defect.
The information regarding defect includes status information. The status information includes information indicating that the defective area is a continuous defect block or a single defect block.
The information regarding defect further includes a pointer to the defective area (the location of the defective area on the disc).
The information regarding defect further includes a pointer to the replacement area corresponding to the defective area.
When the defective area is a continuous defect block, the status information indicates that a pointer to the defective area designates a start location of the continuous defect block or an end location of the continuous defect block. In this case, the status information further indicates that a pointer to the replacement area designates a start location of the replacement block or an end location of the replacement block.
By using these data structures, the defective management mechanism can be implemented in the write-once optical disc.
Further, by using the defective management mechanism described above, it is possible to implement a pseudo-overwrite recording for the write-once optical disc.
With reference to FIGS. 31 and 32, the pseudo-overwrite recording for the write-once optical disc will be described.
As described above, in the defective management mechanism, by using the replacement information such as the information regarding defect or the SDL entry, the physical address at which the data is actually recorded is mapped to another location which is previously allocated, without changing the logical address at which the data is recorded.
When it is instructed to record data at a logical address at which the data has already been recorded on the write-once optical disc, the data is recorded in a sector located at a physical address which is different from the physical address corresponding to the logical address, and the replacement information is updated to maintain the logical address. According to this process, it is possible to overwrite data in a pseudo manner. Hereinafter, such data recording is referred to as a pseudo-overwrite recording.
FIG. 31 shows a data structure after directories and files are recorded in the information recording medium 1 which is a write-once optical disc. In the state shown in FIG. 31, it is assumed that the pseudo-overwrite recording has not been performed.
In the write-once optical disc, the user data area on the disc is managed as a unit of track or session.
In FIG. 31, the user data recorded in the user data area is managed by a file system. A space managed by the file system is referred to as a volume space 2.
In the description below, it is assumed that information recorded in the information recording medium 1 as the volume/file structure of the file system (e.g. descriptor, pointer, metadata partition and metadata file) has a data structure defined in the ISO/IEC 13346 standard or the UDF (Universal Disc Format) specification, unless it is explicitly described on the contrary.
In FIG. 31, a volume structure area 3 and a physical partition 4 are recorded in the volume space 2.
In the physical partition 4, metadata partitions 5a, 5b defined by version 2.5 of the UDF specification are included.
In the physical partition 4, metadata file 6a and metadata mirror file 6b which is the duplication of the metadata file 6a are recorded.
FE (metadata file) 7a and FE (metadata mirror file) 7b, each being a file entry (FE) indicating the recording location in the physical partition 4, are recorded. Further, data file (File-a) 8 and data file (File-b) 9 are also recorded.
All information on the file structure such as a file entry and directory file is allocated in the metadata partition, i.e. the metadata file.
In the data structure defined in the UDF specification, the respective recording locations of the metadata partition 5a and the file set descriptor (FSD) 12 are recorded in the volume structure area 3.
By retrieving the file structure from the ROOT directory using the FSD 12 as a start point, it is possible to access data file (File-a) 8, for example.
Next, in the state shown in FIG. 31, it is assumed that the pseudo-overwrite recording for data file (File-c) Is performed.
FIG. 32 shows a data structure after the pseudo-overwrite recording for data file (File-c) is completed.
Herein, it is assumed that the data file (File-c) is recorded immediately under the ROOT directory on the information recording medium 1.
During recording the data file (File-c), the required information on the file structure is updated or generated in order to add the data file (File-c). Specifically, FE (ROOT) 13 is updated and FE (File-c) 14 is generated, for example.
The data file (File-c) 15 is recorded in an unrecorded area shown in FIG. 31. FIG. 32 shows a state at this time.
When the FE (File-c) 14 is recorded, the FE (File-c) 14 is recorded in the unrecorded area 11a in the metadata partition 5a (i.e. the metadata file 6a).
Next, the pseudo-overwrite recording is performed as if the FE (ROOT) 16 would be overwritten on the FE (ROOT) 13.
In this case, as shown in FIG. 32, the data for the FE (ROOT) 16 is recorded in the spare area 17.
Further, the replacement information included in the disc management information 2 is updated such that the FE (ROOT) 13 is mapped to the FE (ROOT) 16.
After performing the recording process for files, a reproduction operation for reproducing the data file (File-c) 15 will be described.
The location information of FE (metadata file) 7a and the location information of FSD 12 are obtained from the volume structure area 3 of the information recording medium 1.
Next, the file structure is reproduced. In order to reproduce the file structure, the FSD 12 is reproduced based on the location information of FE (metadata file) 7a and the location information of FSD 12.
The location information of the FE (ROOT) 13 is obtained as a logical address from the reproduced FSD 12.
The FE (ROOT) 13 is reproduced based on the location information of the FE (ROOT) 13.
By referring to the replacement information, the FE (ROOT) 16, to which the FE (ROOT) 13 is mapped, is reproduced.
The FE (ROOT) 16 includes the latest ROOT directory file. Accordingly, the FE (ROOT) 16 includes the location information of the FE (File-c) 14.
The data file (File-c) 15 is reproduced using the location information of the data file (File-c) 15 which is obtained from the FE (File-c) 14.
Thus, in the write-once optical disc, it is possible to perform a pseudo-overwrite recording using the defective management mechanism.
However, according to the pseudo-overwrite recording for the write-once optical disc described above, there is a problem that if there is no unrecorded area in the spare area, it is not possible to further perform the data recording even if there is an unrecorded area in the user data area. This is because it is not possible to update file system information.
In particular, in the write-once optical disc, the size of the spare area is fixed at the time when the disc is formatted (initialized), unlike the rewritable optical disc in which the size of the spare area can be extended if required.
It is difficult to determine the size of the spare area appropriately in view of the pseudo-overwrite recording which may be performed in the future.
If the size of the spare area is determined as a relatively large size, the size of the user data area must be reduced. If the size of the spare area is determined as a relatively small size, a problem may be caused. The problem is that it is not possible to further perform the data recording even if there is an unrecorded area in the user data area. In either case, it is not possible to effectively utilize the user data area of the write-once optical disc.
The present invention is intended to solve the problem described above. One of the purposes of the present invention is to provide a drive apparatus capable of utilizing the user data area without any loss in the pseudo-overwrite recording for the write-once optical disc.
According to the present invention, it is possible to provide a drive apparatus capable of utilizing the user data area without any loss in the pseudo-overwrite recording for the write-once optical disc.